A β-diketone compound had been formerly used for applications such as additives and fragrances of synthetic resins. However, in recent years, utilization of the β-diketone compound as a precursor of an organic metal compound that is a raw material for formation of a metallic thin film by chemical vapor deposition methods (such as CVD method and ALD method) is attracting attention. Examples of an organic metal compound in which β-diketones are coordinated, which is useful as a raw material for a chemical vapor deposition method, include organic metal compounds described in Patent Documents 1 to 3. These organic metal compounds are obtained by coordinating 2 to 3 β-diketones to a core metal such as Ru and Ir. These organic metal compounds contain β-diketones as ligands, thereby having advantages such as favorable adhesiveness when a thin film is formed and preferable reactivity to a specific reaction gas (such as hydrogen).

In the above organic metal compounds, those having different substituents of β-diketones (R1 and R2 in Chemical Formula 1) are assumed to be preferable. This is because organic metal compounds having different R1 and R2 can be formed into a liquid state at normal temperature and handling properties of a raw material in a step of thin film formation by a chemical vapor deposition method are preferable (refer to Patent Document 1). In this respect, the organic metal compounds of Chemical Formulas 2 and 3 have different substituents such as a methyl group and an ethyl group as substituents of β-diketones. Then, in order to synthesize organic metal compounds in which such asymmetric β-diketones are coordinated, a β-diketone compound to be a precursor is also required to have an asymmetric property.
Herein, as a method for producing an asymmetric β-diketone compound, basically, a synthesis reaction similar to a symmetric β-diketone compound can be used, and a desired reaction substance having two types of substituents may be used in this reaction. Examples of the method include a synthesis method by a condensation reaction between an ester compound and a ketone compound according to the reaction formula described below (Patent Document 4, Non-patent Documents 1 and 2). In this synthesis method, starting materials (ester compound and ketone compound) are easily obtained, reaction steps are also easy and simple, and the synthesis method is therefore generally used.

In addition, besides the above synthesis method, there is a synthesis reaction of using a β-ketoester as a starting raw material according to the following formula. This synthesis reaction is a method of reacting a β-ketoester and a carboxylic acid halide or a carboxylic anhydride and obtaining a β-diketone compound by a dealkoxycarbonylation reaction of the obtained intermediate product.
